GB1194653A - Fluid Operated Tool - Google Patents

Abstract

1,194,653. Power tools. GARDNERDENVER CO. 30 Sept., 1968 [16 May, 1968], No. 46409/68. Heading B3N. A fluid operated nut runner, or screwdriver has a control means in communication with a motor inlet port 50, the control means including a movable element 64 having opposed surfaces 67 and 70 subjected to fluid pressure forces and operable in response to the fluid pressure forces to shut off the flow of fluid to the motor. Operation.-A trigger 54 is depressed allowing fluid at supply pressure to enter a chamber 40 where with the assistance of a spring 52, a fluid supply valve 32 is moved to the right permitting fluid to flow through an opening 44 and thus to the motor 16. When the pressure in the motor inlet 50 reaches a predetermined value, this value is sensed in a cavity 72 and the resultant pressure on the surface 70 is higher than that which a preset pressure in a cavity 68 can exert on the surface 67. The element 64 thus moves upward in which position chamber 40 is vented, the pressure in area 26 overcomes the spring 52 thus closing the fluid supply passage to the motor. Movement of element 64 upwardly is augmented by fluid at supply pressure being provided in response to shifting of the element 64 via a conduit 16, Figs. 2-4 (not shown). The cut-off point of the motor can be adjusted by controlling the pressure in cavity 68 through a pressure regulating needle valve 78.